I have the genomes of several isolates of a parasite, and I would like to investigate synonymous/non-synonymous substitution for identifying potential antigens, as well as SNPs genome-wide and I am wondering how well BWA/GATK are suited for this purpose. I've been told that BWA is only very good with sequences <2% divergent, and some of the antigens in this specie are known to be >20% divergent. However, I also know that GATK does local realignments of indels. So I would specifically like to know - is BWA/GATK good for looking at substitutions/SNPs in highly variable genes, and if not which other alignment tools are compatible and appropriate for this purpose?